a. Field of the Invention
The present invention relates generally to devices for therapeutic application of magnetic fields, and, more particularly, to a compact, portable device for therapeutic application of weak, pulsed electromagnetic fields for human and animal applications.
b. Related Art and Discussion
The therapeutic value of pulsed electromagnetic fields has gained acceptance through the course of studies and clinical applications. Magnetic fluxes are known to penetrate deeply into human tissue with little attenuation, and have been observed to promote both bone and tissue regeneration. Although the physiological mechanism involved is not fully understood and is the subject of competing hypotheses, it is theorized that magnetic field exposures exert the observed effects through induction of electrical currents in the tissues. Moreover, it is believed that these effects occur on a molecular or cellular level.
A number of systems and devices have been developed to apply the observed benefits of pulsed electromagnetic fields in a therapeutic environment. Many or most of these devices have been directed to the promotion of bone growth, specifically the therapeutic treatment of bone fractures. While mostly successful for their intended purpose, difficulty in the use and application of these devices has limited their benefits in the treatment of surrounding soft tissues (e.g., muscles and tendons). field, although a few devices have been developed that use somewhat weaker fields. These devices also employ a comparatively long ramp up to full pulse strength. As a group, these devices have been ungainly and difficult to apply, especially outside a clinical setting, and consequently have limited utility in treatment of soft tissue traumas.
In the course of extended clinical observations, Applicant has found that low-strength, pulsed electromagnetic fields (i.e., fields having a strength more on the order of the naturally occurring magnetic field of the earth) produce results superior to high-strength magnetic fields when applied to soft tissue trauma. Moreover, Applicant has found improved results may be achieved by employing pulses of very brief duration (200 nanoseconds). Examples of such soft tissue trauma include muscle and tendon strain, as well as the more serious traumas associated with fractures and wounds.
Commensurate with these observations, Applicant has developed the nonbonding hypothesis that brief duration pulses and short ramp times (i.e., the time between 0 and maximum magnetic flux) may enhance molecular orientation or other molecular activity in the affected tissues, thereby promoting more rapid healing. In accordance with this hypothesis, one possible mechanism of the increased healing rates may be as follows. Trauma results in oxidative stress, and healing is promoted by neutralizing the oxidant species at the trauma site. Oxidant species are neutralized by naturally occurring antioxidants in the body, however the rate of oxidant species neutralization is greatly increased by using a pulsed electromagnetic field (PEMF) as a momentary homogenous catalyst which aligns reactive (charged) surfaces across flux lines in the PEMF. Through observation and clinical study, Applicant has noted that the more quickly the magnetic field is introduced to and then, after creating its effect, removed from the injured living system, the greater the efficiency of interaction, resulting in increased reaction rates, faster neutralization, and a corresponding faster rate of healing. Give the picosecond nature of chemical reactions, the short, nanosecond catalyst may be advantageous in that it is removed from the tissue before causing an overall slowing of the molecular activity that would outweigh its organizational advantages. Longer, millisecond pulses, by contrast, may create a net slowdown. Moreover, it is hypothesized that the effect of the low-strength magnetic field is superior to the commonly applied high strength fields due to the fact that the low-strength field is not dramatically dissimilar from that in which living systems developed and which all organisms are adapted, i.e., the magnetic field of the earth itself.
Consequently, while the pulsed electromagnetic devices found in the prior art emit sine wave-configured field pulses with relatively slow ramp times, it is Applicant's assertion that pulses of short duration with short ramp times and lower field strengths result in significantly improved injury recovery rates.
As was noted above, prior PEMF therapy devices have also been so large and costly as to be unsuitable for much therapeutic applications, let alone individual use. For example, many are heavy (e.g., several hundred pounds), stationary devices which often surround an entire limb or body of the patient. The large physical size, as well as the broad PEMF footprint, limits their therapeutic application in discrete, less accessible anatomical locations where isolated treatment may be desired. In at least some instances, the size of these devices is driven by the magnetic coil technology that is used, coupled with the perceived need to propagate exceedingly strong magnetic fields. In any event, such devices wholly unsuitable for home use; the benefits are therefore limited to infrequent clinical visits, rather than daily or hourly application, except in the case of hospitalized patients.
Accordingly, there exists a need for a device for pulsed electromagnetic field therapy of soft tissue trauma that propagates a comparatively low strength magnetic field capable of penetrating to muscles, tendons and like tissues. Furthermore, there exists a need for such an apparatus that generates such fields with a comparatively short pulse duration and short pulse ramp times. Still further, there exists a need for such an apparatus that is sufficient inexpensive, portable, and suitable for home use on a frequent or as-needed basis, and which allows treatment in discrete anatomical locations as desired.